The Hama WiFi Steckdose 00176533 is a smart plug that comes with a Schuko-F plug. It is meant turn any regular wall outlet into a smart outlet. It sports a button for manual operation and two LEDs, a red one in sync with the relay status and the other blue one for the WiFi status.

There is a identically looking one with a different article number available, these instructions here cover the 00176533 model (written on the rear label).

If someone has the 00176552 model and can confirm these instructions work for this model too, please report.

There is a custom WiFi PCB based on a TYWE3S module soldered perpendicular into the main PCB

I found it easiest to remove the add on board by desoldering it from the main PCB and attach some wires with a pinheader to it, supplying it with 3.3V from my USB-UART converter.

Looks something like this then:

GPIO 0 must be held on GND while connecting it to the UART converter. Can be flashed normally then. Flash size is 1MegaByte